The situation is not quite as intense in the -66kg division although there is plenty of competition there. The dominant player at -66kg is three-time World Champion Masashi Ebinuma, whose grit and determination in the final of the 2013 Rio Championships made him the hero of the tournament.
Ebinuma won all his three world titles in spectacular fashion.
His opponent, Azamat Mukanov, from Kazakhstan had repeatedly attacked him with an illegal waki-gatame. Incredibly, the referee and video judges let the fight go on instead of giving Mukanov hansoku-make. In one particularly vicious attack, Mukanov nearly broke Ebinuma's arm and certainly damaged it. But Ebinuma fought back, throwing Mukanov with an ouchi-gari for an indisputable ippon -- a legendary performance if there ever was one.
Japan has another top player in Masaaki Fukuoka, who is often the alternate at -66kg. He's had some respectable wins in his career though nothing close to matching Ebinuma's brilliant results. But Fukuoka is now 30 years old and is not a threat to Ebinuma. There is also 2010 World Champion Junpei Morishita, who is only 24, but he hasn't fought internationally since the middle of last year and may have retired.
Abe & Takaichi beat Ebinuma in the 2014 Tokyo Grand Slam
The real threats are 21-year old Kengo Takaichi, who gave a creditable performance at the 2014 Chelyabinsk World Championships; and 17-year old Hifumi Abe, the 2014 Youth Olympic Games Champion. It's interesting to note that both Takaichi and Abe defeated Ebinuma in the 2014 Tokyo Grand Slam (Abe went on to win the gold).
Ebinuma is still the clear favorite for the -66kg spot on Japan's team but both Takaichi and Abe are hot on his heels. Both are hungry and look extremely dangerous. As with the -73kg division, at -66kg Japan is rather spoilt for choice.